Endocrine System Development

Introduction

Human adrenal gland (Week 10)

The endocrine system resides within specific endocrine organs and both organs and tissues with other specific functions. Epithelia (ectoderm and endoderm) form the majority of the “ductless” endocrine glands like gastrointestinal and skin associated “ducted” glands. Differentiation of several also organs involves a epithelial/mesenchye interaction, seen in repeated in many differentiation of many different tissues. The endocrine glands produce hormones, which are distributed by the vascular system to the many body tissues, subsequently these organs are richly vascularized.

Hormones are recognised by either cell surface receptors (modified amino acids, peptides, proteins) or cytoplasmic/nuclear receptors (steroids). Hormones “orchestrate” responses in other tissues, including other endocrine organs, and these overall effects can be similar or different in different tissues. In addition, these hormone effects (like music) can be rapid, slow, brief, diurnal, or long-term. Hormone effects can be mimicked, stimulated, and blocked by therapeutic drugs, nutritional and environmental chemicals.

The human fetus is dependent upon endocrine development for hormones, which support normal development. Peripheral endocrine glands (thyroid, pancreas, adrenals, gonads) form early in the second month from epithelial/mesenchye interactions and differentiate into the third month. The fetus also has a unique hormonal system that combines not only its own developing endocrine system, but also that of the placenta (More? see Placenta notes) and maternal hormones.

Abnormal endocrine development/function can impact on many different systems. For example, insufficient maternal dietary iodine impacts on fetal thyroid gland thyroid hormone production, which in turn can lead to abnormal neural development. Alternatively, we now know many environmental and therapeutic chemicals have a wide range of effects on the endocrine system.

Sex hormones from the gonads have significant effects prenatally and postnatally, specifically at puberty with a role to play in male/female biological maturity and have wide actions throughout the body.

--Mark Hill 09:25, 14 April 2010 (EST) Page Template only - content from original UNSW Embryology site currently being edited and updated.

Some Recent Findings

• Relative roles of the different Pax6 domains for pancreatic alpha cell development. Dames P, Puff R, Weise M, Parhofer KG, Goke B, Gotz M, Graw J, Favor J, Lechner A. BMC Dev Biol. 2010 Apr 9;10(1):39. PMID: 20377917

"The transcription factor Pax6 functions in the specification and maintenance of the differentiated cell lineages in the endocrine pancreas. It has two DNA binding domains, the paired domain and the homeodomain, in addition to a C-terminal transactivation domain. The phenotype of Pax6-/- knockout mice suggests non-redundant functions of the transcription factor in the development of glucagon-expressing alpha-cells as this cell type is absent in the mutants."

Textbooks

In general, not dealt with as a system in many textbooks, so various chapters: nervous system, head, gastrointestinal tract, reproductive organs, etc.

• Human Embryology (3rd ed.) Larson Chapter 9 Gastrointestinal, Chapter 10 Gonad, Kidney Chapter 12 Head
• The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Chapters 10: p230-233; Ch12: p280-282; Ch13: p319-347

Objectives

• Understand the main steps in the development of the thyroid, parathyroid, adrenal, pituitary, pineal glands, thymus and gonads.
• Have a general understanding of the chief functions of these endocrine organs.
• Understand the endocrine contribution to embryo development.
• Understand the endocrine role of the placenta during development.
• Have a general understanding of different types of hormones and their signaling actions.

References

Search PubMed

Search April 2010 "Endocrine Development" - All (14277) Review (4620) Free Full Text (3140)

Search Pubmed: Endocrine Development

Additional Images

Embryonic Histology

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  Stage 22 - Pancreatic duct

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  Stage 22 - Adrenal gland

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  Week 10 - Adrenal gland

Adult Histology

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  Pineal (high power)

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  Thyroid (low power)

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  Thyroid (high power)

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  Parathyroid (low power)

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  Parathyroid (high power)

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  Pituitary - adenohypophysis

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  Pituitary - adenohypophysis

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  Pituitary - neurohypophysis

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  Adrenal - Cortex and Medulla

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  Adrenal - Cortical Zones

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  Adrenal - Zona Reticularis and Medulla

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  Pancreatic islet

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Cite this page: Hill, M.A. (2024, June 27) Embryology Endocrine System Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Endocrine_System_Development

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G